Premium oils intraoperative consideration

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Intraoperative consideration
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Introduction
 In selecting the most appropriate intraocular lens (IOL),
ophthalmic surgeons should keep in mind that there is no
single "best" IOL for every patient.
 Active listening to the patients' desires for their vision after
cataract surgery is critical in selecting the most appropriate
IOL for any patient.
 Matching the strengths (and avoiding the weaknesses) of the
various IOLs to the patients' needs and wants for visual
functioning will most likely result in both patient and surgeon
satisfaction.

Introduction
 Selecting the optimal IOL for each patient requires making
a concerted effort to define and manage
postoperative expectations as well as
making keen observations about patient personalities

Expectations And Personality
 Compromise is essential
In recent years, the category of premium lenses has grown to include toric, accommodating
and multifocal IOLs.
For all the new alternatives, there’s still one qualification they all share: they require some
flexibility on the patient’s part.
 The technology of many of these lenses requires a degree of
optical compromise
substantial financial contribution

Personality assesment
 The questionnaire reviews
seven specific situations in which the patient would like to see
well without glasses after surgery
the patient’s feelings and requirements about
○ night vision; and
○ distance vision preferences during the day and night
 The questionnaire also asks the patient to indicate on a
sliding scale their personality from “easy going” to
“perfectionist.”

Lens Selection And Screening
 For a patient without astigmatism who wants the best possible distance vision
premium choice is a monofocal IOL
 For a patient with same distance-vision goal, some astigmatism and reader toleration capability
premium choice is monofocal IOL and astigmatic keratotomy.
 For a patient has moderate astigmatism, wants the best distance vision and is OK with readers
premium choice is a toric IOL.”
 For a patient wore monovision contact lenses before and without problems
premium choice is monovision.
 For a patient who want a broad range of focus in each eye
premium choice is a multifocal IOL
 For a patient with serious astigmatism who can live with readers
premium choice is a toric IOL and astigmatic keratotomy.

Inraoperative considerationt
General Issues
 A centered, properly sized capsulorhexis is important for IOL
function and power selection.
 An even anterior capsule overlap of 360 degrees allows IOL
centration despite contraction of the anterior capsule.
 Placement of a multifocal IOL is controversial when an anterior
capsule tear is present as these tears may or may not lead to
IOL decentration in the long term
 A well-centered anterior capsulotomy can be used to fixate an
IOL when the posterior capsule is not stable; with reverse optic
capture, the haptics are placed in the bag and the optic is
prolapsed anteriorly into the sulcus.

General Issues
 The broad objectives in the management of any posterior
capsule rupture are to prevent vitreous prolapse, perform
meticulous removal of the vitreous if it does occur, completely
remove residual lenticular material, and implant a multifocal
IOL in the capsular bag.
 In case of a small, relatively central, well- demarcated posterior
capsule rupture, converting it into a posterior continuous
curvilinear capsulorhexis

General Issues
 However, in case of a large posterior capsule rupture with
inadequate bag support, it may be preferable to implant a
monofocal IOL in the ciliary sulcus with capture through
the anterior capsulorhexis margin.
 If possible, it is better to avoid implanting a 1- piece
multifocal IOL in the ciliary sulcus due to risk for pigment
dispersion, inflammation, and hemorrhage; at the least, it
is important to have a 3-piece multifocal IOL available
should sulcus placement be required

Aberrations ( multifocal & toric )
 the visual quality of a premium IOL is best when the spherical equivalent
(SE) is close to plano and postoperative regular corneal astigmatism is
0.50 D or less, but other aberrations, such as coma and spherical
aberration, may also reduce visual quality.
 The anterior corneal coma values greater than 0.32 mm may result in
intolerable dysphotopsia in the presence of a diffractive optics multifocal
IOL.
 Placing a multifocal IOL behind a multifocal cornea runs the risk of an
additional loss of contrast with a reduction in visual quality.

Pupil issues
 Patients with a large pupil are at increased risk for glare dysfunction
following surgery.
 Patients with an atrophic iris are at risk for increased glare,
photosensitivity, and often zonular weakness
 The small pupil may require expansion for a safe capsulorhexis and
nucleofractis. A decentered capsulorhexis is a risk factor for a decentered
IOL
 Iatrogenic mydriasis could lead to dysfunction of the multifocal IOL with
un- wanted reflections and image confusion.
 In addition, pupil abnormalities such as ectopic pupil and coloboma are
often associated with weak zonular fibers.

Zonular Issues
 The amount of decentration that results in a significant
loss of optical quality, measured by modulation transfer
function, is reported to be approximately 0.75 mm to 1.00
mm for refractive and diffractive multifocal IOLs.1
 Studies have reported significantly better visual acuity with
implantation of a CTR with multifocal IOLs, especially for
rotationally asymmetric multifocal IOLs

Retinal Issues
 The potential problems are 2-fold: impaired vision for the patient and impaired
fundus visualization for the treating physician.
 Testing macular function in patients with known macular pathology is
important and includes simple near acuity, pinhole testing, super pinhole
testing (a pinhole with a C3.00 D lens for near acuity), the red-stripe test, a
potential acuity meter, and the Retinal Acuity meter.
 One might also chose to perform a macular OCT test to look for subtle or occult
pathology, as well as to quantify mild recognized macular disease.

Optic nerve Issues
 Appropriate tests to evaluate optic nerve structure and/or
function in the presence of a cataract include pupil re-
action (direct and consensual), automated perimetry
visual field testing, ophthalmoscopy, and OCT optic nerve
evaluation.

CNS / motility Issues
 In addition to good uncorrected distance visual acuity
(UDVA), the ability to perform common near activities
without spectacles, such as reading and viewing
photographs, might be advantageous, particularly as the
dementia progresses.
 The involvement of a close family member or power of
attorney/caregiver in the decision would generally be
advisable because it may be difficult for the
ophthalmologist to determine the patient's actual cognitive
abilities and comprehension of the issues.

Premium Toric IOL selection
 In the last 3 decades, advances in cataract surgery have dramatically
improved patients' outcomes, increasing expectations regarding visual
results.
 It has been estimated that 30% of cataract patients have more than 0.75
diopters (D) of corneal astigmatism, that 22% have more than 1.50 D,
and that 8% have more than 2.00 D(1,2)
.
 Since post-surgical residual astigmatism can compromise uncorrected
distance visual acuity (UDVA), correction of corneal astigmatism is a
critical element of modern cataract surgery.

Surgically induced astigmatism
 When calculating the power of toric IOLs, it is also important to consider
the surgically induced astigmatism (SIA).
 The SIA is a result of flattening in the meridian of incision and
steepening 90º away
 The amount of SIA depends on several factors, including
the size, shape, and location of the incision,
suture use, and
the response of the patient's cornea.
 Each surgeon should calculate his/her own SIA, which can be done using
a standard astigmatism vector analysis.
One of the websites that can be
used for this purpose is http://www.doctor-hill.com/

Toric IOL alignment and eye marking
techniques
 The marks on the IOL indicate the flat meridian (plus cylinder axis) of
the toric lens.
 The precise relation between residual cylinder and meridional
misalignment is sinusoidal, although,
within 15 degrees of misalignment, the amount of residual cylinder is approximately
3.5% per degree.
A 30º misalignment induces an estimated residual cylinder of 100% of the toric
IOL cylinder power,

Marking
 In the OR, use a standard orientation marker to find and
mark the correct steep axis and sometimes reinforce it
with insulin needle
 Make the 2.4-mm primary incision at 20° in the left eye
and 200° in the right.
 Moving incisions to steep axes makes surgery more
difficult and introduces unnecessary variables.

capsulorhexis and implanting and orienting IOL
 Create 5-mm diameter well center capsulorhexis unless the patient is highly
myopic. For highly myopic patients, create a 4.6-mm capsulorhexis
 Cohesive OVDs e.g. Healon (AMO) or Provisc (Alcon) is preferred over the
dispersive agents. Cohesive OVDs are less likely to coat the IOL surface and are
easier to remove at the end of the case.
 Toric iol should be grossly aligned about 10-15 degrees counterclockwise of the
final desired lens position.
 Of course, IOLs need to be oriented properly and virtually all viscoelastic must
be removed from in front of and behind the optic.

Toric IOls
Proper IOL alignment, centration
 Angle alpha is the angle between the geometric centers of the
cornea and crystalline lens (or IOL) forming the optical axis and
visual axis of the which induces small amounts of astigmatism and coma.
 For spherical surfaces this astigmatism and coma are on the order of 0.25 D to
0.50 D and have little effect on the final refraction.
 For toric surfaces (cornea and IOL), the tilt and decent ration result in secondary
astigmatism, coma and other higher-order aberrations.
 For corneal astigmatism greater than 3 D, the induced aberrations are often the
limiting factor in the visual quality.
 The optimal location of the IOL on the 3 mm to 4 mm pupil should be decentered
slightly nasal in the bag to achieve pupillary centration.
 For toric IOLs, due to this decentration relative to the cornea, it
is usually impossible to align the IOL toric marks with the marks
on the limbus; at best they can be parallel to this axis

Rotating IOL and visco removal
 accomplish preliminary positioning with the I/A tip just 10° shy of the desired
orientation. then make the final adjustment with a 30-gauge cannula on a BSS syringe (.
 When appropriately oriented, a gentle nudge posteriorly will hold it there securely. This
step increase IOL contact with the posterior capsule, decreasing the incidence
of postoperative rotation.
 If the IOL over-rotates, viscoelastic should be injected into the eye and the above steps
repeated as it can only be rotated clockwise.
 Overinflate the chamber and overhydrate the incision
 Some surgeon recommend just supine position up to one hour after operation for
preventing undesirable rotation

Personality assesment
 Note that the questionnaire will eliminate the problem of
dissatisfied patients.
 patients who rated their personality exactly midway on a
linear scale between “easy going” and “perfectionist”
tended to be slightly less happy postoperatively even with a
result the surgeons judged to be optically perfect.
✕

Lens Selection And Screening
 Goals first
it is the patient’s goals that determine IOL selection.
 The lens only becomes “premium” if it helps the patient
achieve the sight goal.
 You should interviews patients about their lifestyle habits
to help them attain their desired vision.

Patient education
 Educating patients on their experience before and after
cataract surgery gives they
proactively manage their experience and their mindset,
driving positive outcomes.
 Explore the tabs below to learn more.“If you properly educate
95% of your patients, the 5% whom you overlook can make
your life very difficult.
 This can be particularly maddening when a frustrated patient
has achieved exactly what you … expected and extensively
discussed with the patient as the surgical goal.”

Patient education
 Surgeons should be prepared to consider declining to
operate on patients who never reach a level of appropriate
expectations
 surgeons also can become the victims of their own good
outcomes. “As results improve, more patients assume that
flawless vision is routine and expected.”

Patient education and selection
Potential candidates:
Enjoy activities and hobbies that require visual acuity at
multiple distances, such as reading, driving and attending
sporting or theater events
Want to be less dependent on spectacles
Have a relaxed, adaptable personality
Have presbyopia or myopia
Fall within the available IOL power range
Qualify for bilateral implantation
Have no preexisting ocular pathology
Have had no previous refractive surgery

Patient education and selection
Patients who may not be ideal candidates:
Are not opposed to (or even enjoy) wearing glasses
Are impatient, unwilling or unable to adapt
Have unrealistic expectations about their outcomes
Have a preexisting ocular pathology, such as dry eye, uncontrolled
glaucoma and keratoconus
Have had prior refractive surgery
These patients may be better candidates for a monofocal IOL.

Hit the refractive target
 Delivering the best refractive results depends on
precise preoperative measurements and
meticulous surgical technique.
 This is a multifactorial process that includes
obtaining accurate keratometry and axial length values
detecting and treating tear film and corneal irregularities
being cognizant of surgically induced astigmatism, and standardizing surgical
technique for wound and capsulorhexis construction.
It is also important to detect any other abnormalities of the cornea, retina, and optic
nerve that could contribute to reduced vision or could increase the risk of a
complication.

Hit the refractive target
 Similarly, specialized testing is often necessary for surgical planning.
Corneal topography must be performed to detect pathology and identify
astigmatism.
Corneal pachymetry is used to determine whether the patient can safely undergo
laser vision correction for a residual refractive error
macular OCT in all patients desiring a multifocal IOL because OCT can detect
subtle macular pathology that may not be visible on direct exam and that could
preclude the use of such a lens.

Reduce postoperative
complications
 This starts with a
postoperative topical medication regimen of a
○ potent, broad-spectrum antibiotic to prevent infection, and
○ A steroid and NSAID to treat inflammation and prevent cystoid
macular edema (CME). administer a topical steroid and NSAID
for 4-8 weeks after surgery depending on the patient’s risk of
developing CME (i.e., increased risk with diabetes, uveitis, retinal
vein occlusion, epiretinal membrane).

Manage outcomes
 Proper postoperative counseling is also important, so any
issues that arise should be addressed and treated
promptly.
 This process should be initiated prior to surgery by
adequately preparing patients as to what to expect after
surgery. Doing so will reduce the amount of postoperative
chair time.
 Often patients just want their concerns validated, and
simple reassurance is sometimes all that is needed.

Manage outcomes
Blurry vision
 The treatment of reduced vision depends on the etiology.
 The most common cause of postoperative blurred vision is
a residual refractive error
treat this with laser vision correction once the refraction has stabilized (I like to wait at least 3 months).
 Dry eye is also a frequent cause of blurry vision
carefully evaluate all surgical patients preoperatively for dry eye and treat it aggressively before and after
surgery.
 CME must be considered when patients develop deterioration in vision 2-6 weeks
after surgery
this complication very rare (<1%) with the use of postoperative topical NSAIDs in addition to steroids.
 posterior capsular opacification can cause reduced vision in the early or late
postoperative period
perform laser posterior capsulotomy earlier for these patients.

Manage outcomes
Halos
 Halos around lights at night are a form of dysphotopsia
that is common with multifocal IOLs.
warn patients that this occurs and is normal. The halos
improve with time and usually resolve within 6-12 months.
When patients are having difficulty with halos, constricting the
pupil with Alphagan-P or pilocarpine can be quite helpful.
Vision training may be beneficial as well.
Ultimately, an IOL exchange can be considered but is rarely
needed.

Manage outcomes
Poor near vision:
 Variable near vision is also a limitation of presbyopia-correcting IOLs.
warn all patients of this possibility prior to surgery and emphasize
that these lenses will reduce dependence on glasses but do not always
eliminate the need for glasses, particularly for reading.
After surgery, near vision tends to continue to improve over weeks to
months as patients adapt to their new vision and learn how to see with
the lens.
explain to patients that these lenses work best binocularly so the
near vision will improve after surgery on their second eye.
show patients what their near vision would have been had they not
had a presbyopia-correcting IOL, and this can be easily demonstrated
by having them read at near through -2.50 or -3.00 D lenses.

 Corneal astigmatism can be surgically treated with
adjustment of wound size and location,
peripheral corneal relaxing incisions,
additional clear corneal cataract incision along the steep
meridian,
laser refractive surgery, or
toric intraocular lenses (IOLs).

 The ideal patients for toric IOL implantation are those
with regular astigmatism,
○ although previous papers have also shown good outcomes in cases
of
stable, mild central irregular astigmatism, such as
- patients with mild to moderate stable keratoconus
- pellucid marginal degeneration and
- post-corneal transplant.
 Toric IOLs should be avoided in patients with
corneal dystrophies that might need a corneal transplant in
the future
patients with potential capsular bag instability

Measuring corneal astigmatism and calculating toric
IOLs
Devices Various measuring methods are available, including
manual keratometry,
automated keratometry,
corneal topography,
slit-scanning technology,
optical coherence tomography, and
Scheimpflug imaging.
 The first three methods measure the anterior corneal surface only.
Using a standardized corneal refractive index, most commonly 1.3375, they assume a fixed
posterior:anterior corneal curvature ratio to calculate total corneal power and astigmatism.
 On the other hand, slit-scanning technology, optical coherence tomography and
Scheimpflug imaging measure the anterior and posterior corneal surface.
Therefore, they provide total corneal power and astigmatism based on the measured anterior
and posterior corneal data.

Measuring corneal astigmatism and
calculating toric IOLs
The role of the posterior cornea
 Recent studies)
have shown the importance of considering the posterior
corneal surface when determining total corneal astigmatism and
planning astigmatism correction. The posterior cornea acts as a minus
lens.
 It generally has a steeper vertical meridian, and remains steeper vertically
with increasing age.
 The anterior corneal steeper meridian is also commonly oriented
vertically in younger individuals, but shifts towards the horizontal
meridian as patients get older.
 Thus, in general, posterior corneal astigmatism partially compensates for
anterior corneal astigmatism in young adults and increases total corneal
astigmatism in older individuals.

 The mean magnitude of posterior corneal astigmatism is - 0.30 D.
 Koch et al. have shown that one cannot accurately predict the posterior
corneal astigmatism based only on anterior corneal measurements.
 They found maximal values of
posterior corneal astigmatism of over 0.8 D in corneas that had WTR astigmatism
on the anterior corneal surface and
of over 0.5 D in corneas that had ATR corneal astigmatism on the anterior corneal
surface.
 The correlation between anterior and posterior corneal astigmatism was
moderate when the steep anterior meridian was aligned vertically, weak
when it was oriented obliquely, and absent when it was aligned
horizontally

 They found an overestimation of with-the-rule astigmatism of
1) 0.5 to 0.6 D in eyes that had WTR astigmatism on the anterior
corneal surface and
2) 0.2 to 0.3 D in eyes that had ATR corneal astigmatism on the
anterior corneal surface.
 Posterior corneal astigmatism can be measured directly using
devices such as the dual Scheimpflug analyzer, although the
accuracy on an individual basis is still uncertain.
Alternatively, one can account for posterior corneal astigmatism
using nomograms such as the Baylor Toric IOL Nomogram

Calculating toric IOL power
 Determination of the optimal IOL toricity can be performed
using
a calculation program provided by the manufacturer,
calculation methods described in the literature
or nomograms, such as the Baylor Toric IOL Nomogram
 The cylindrical power of the toric IOL should be chosen based
on the total corneal astigmatism, taking into consideration
anterior corneal astigmatism, posterior corneal astigmatism,
and SIA.

 Another factor to consider is the impact of effective lens position and of the
spheroequivalent power of the IOL on the effective cylinder power of the IOL at
the corneal plane.
 Effective toricity of the IOL diminishes with increasing ACD and lower IOL
spherical power.
The Holladay IOL Consultant Program and the Tecnis Toric Calculator (Abbott Laboratories Inc., Santa
Ana, USA)(
take this into account in its calculation of toric IOL power.
 Furthermore, when choosing the IOL toricity, it is desirable to leave patients with
slight WTR astigmatism, due to the normal tendency for astigmatism to drift
ATR with advancing age.
Thus, leaving this slight with-the-rule astigmatism prolongs the period of time in which the patient's
corneal astigmatism is compensated by the toric IOL

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